Galen (130-200), Greek physician, anatomist, physiologist, philosopher, and lexicographer, was probably the most influential physician of all time.

Throughout his life Galen was a prolific writer, producing his first books, Three Commentaries on the Syllogistic Works of Chrysippus, at the age of 13 and his last, Introduction to Dialectics, in the year of his death. His total output has been estimated at more than 2 1/2 million words. Those of his writings which survive make up over half the extant works of ancient medicine.

Various birth dates from 127 to 132 have been suggested, but 130 is generally accepted. Galen was born at Pergamon, Asia Minor, into a well-to-do family with strong scholarly traditions and influenced by the renaissance in Greek culture which had started at the end of the 1st century A.D. This renaissance had led to increasing Hellenization of the Roman world, the adoption of Greek models of learning, and the use of Greek as the cultural language.

Galen's father, Nicon, mathematician, architect, astronomer, philosopher, and devotee of Greek literature, was not only his sole instructor up to the age of 14, but the example of Stoic virtues on which Galen consciously modeled his own life. In his book On the Passions and Errors of the Soul he says he was "fortunate in having the least irascible, the most just, the most devoted of fathers," but of his mother he says "she was so very much prone to anger that sometimes she bit her handmaids; she constantly shrieked at my father and fought with him." Galen continues, "When I compared my father's noble deeds with the disgraceful passions of my mother I decided to embrace and love his deeds and flee and hate her passions." He defined passion as "that unbridled energy rebellious to reason" and had its control as one of his life's aims. Not surprisingly, perhaps, he himself remained unmarried.

Philosophical and Medical Training

In his fourteenth year Galen attended lectures given by Stoic, Platonic, Peripatetic, and Epicurean philosophers from Pergamon. Encouraged by Nicon, he refused to "proclaim [himself] a member of any of these sects" and said "there was no need for [the philosophy] teachers to disagree with one another, just as there was no disagreement among the teachers of geometry and arithmetic." Later in life he adopted the same attitude to the medical sects, and he urged physicians to take whatever is useful from wherever they find it and not to follow one sect or one man because that produces "an intellectual slave."

Galen relates that Nicon "advised by a dream made me take up medicine together with philosophy … if I had not devoted the whole of my life to the practice of medical and philosophical precepts, I would have learned nothing of importance … the great majority of men practicing medicine and philosophy are proficient in neither, for they were not well born or not instructed in a fitting way or did not persevere in their studies but turned to politics."

Galen, being well born, fittingly instructed, and eschewing politics, persevered with his studies at Pergamon for the next 4 years, as he puts it, "urging [myself] above [my] companions to such a degree that I was studying both day and night." His first anatomy teacher was Satyrus, a pupil of Quintus, who through his students played a major role in the resurgence of anatomical activity that culminated in Galen's work.

Nicon died in 150 and the following year Galen went to Smyrna. While there he wrote his first treatise, On the Movements of the Heart and Lung. In 152 he went to Corinth and on to Alexandria, where he remained for 4 years studying with Numisianus, Quintus's most famous pupil. Although Galen admired Numisianus and "the physicians [who] employ ocular demonstrations [of human bones] in teaching osteology," he tells us that "in Alexandria the art of medicine was taught by ignoramuses in a sophistical fashion in long, illogical lectures to crowds of fourteen-year-old boys who never got near the sick." He "went away surprised and sorrowful—sorrowful at [Julian the sectarian methodist's] lack of sense, and surprised … there could be sufficient stupid pupils to fill his classes."

To counteract the poor teaching and the misunderstandings of the students, Galen produced a number of dictionaries, both literary and medical. He also started a major work, On Demonstration. Unfortunately, no copy survives.

Physician to the Gladiators

In 157 Galen returned to Pergamon, where he "had the good fortune to think out and publicly demonstrate a cure for wounded tendons" which gained him, in 158, the position of physician to the gladiators. He was reappointed annually until the outbreak of the Parthian War in 161.

The traumatic injuries of the arena provided Galen with excellent opportunities to extend his knowledge of anatomy, surgery, and therapeutics, and throughout his life he drew on this fund of experience to illustrate his arguments. While physician to the gladiators, whose daily lives can be reconstructed from his writings, Galen produced some of his most original work, including his demonstration of the part played by the recurrent laryngeal nerve in controlling the production of the voice. This for him and his contemporaries had wide implications, since it impinged on their ideas of the soul.

Practice in Rome

In 163 Galen went to Rome, where he was befriended by the philosopher Eudemus and the consul Flavius Boethius. Galen's public anatomical demonstrations and his success as a physician so aroused the jealousies of the Roman physicians that Eudemus "warned him he was putting himself in danger of assassination." Galen, who accepted the Stoic teachings "to scorn honors and worldly goods and to hold only truth in esteem," scorned the self-seeking of his adversaries and deplored their inability to understand honesty of motive and intellect when they encountered it. He says "his training and studies [did] not fit him to cope with the ignorance and craftiness of his enemies," yet he felt it imperative "to continue to speak out freely." This passion to disseminate knowledge as widely and as publicly as possible is the key to understanding Galen and is the explanation of much of the polemical writing he directed at those who set themselves up as authorities and teachers and who either passed on false information or secretively withheld knowledge in their possession.

Galen returned to Pergamon in 166. However, a severe outbreak of plague among the Roman troops in Aquileia in 168 caused the emperors Marcus Aurelius and Lucius Verus to send for him and appoint him physician-in-ordinary. In 169 Marcus made Galen physician to his son, Commodus (emperor 180-192); and so until 175, when Commodus rejoined Marcus on his military campaigns, Galen lived in one or another of the imperial country houses. During this time he completed his major physiological work, On the Usefulness of the Parts of the Body in 17 books, and wrote another major physiological treatise, On the Natural Faculties, and many other treatises. In 176, as physician to Marcus, Galen returned to Rome permanently. Now under imperial protection, he continued his writing, lecturing, and public demonstrations.

In the winter of 191/192 a fire destroyed most of Galen's library. Yet in spite of this loss (which he met with Stoic calm, saying "no loss was enough to cause me grief"), we are very well informed about his writings, because he wrote two treatises on his own books and their order of production. The first he wrote as a young man when "a certain book … plainly inscribed 'Galenus Medicus' proved on inspection … to be a forgery." The second was compiled in 198. Both works provide authoritative information on the authenticity of his writings and are major sources of biographical detail.

From 179 to his death in 200, Galen continued his medical research and writings, producing such major works as The Method of Cure. However, during his last decade he wrote in a more philosophical vein, giving us such treatises as On the Equality of Sin and Punishment, The Slight Significance of Popular Honor and Glory, and The Refusal to Divulge Knowledge. His last work was titled Introduction to Dialectics.

Assessment of Galen

That Galen was a man of his time is shown by his success and rapid preferment, by his acceptance of dreams as sound directives for action and treatment, and by his acceptance of the Hippocratic tradition and of the social role of public prognostics. That he provoked such strong reactions shows him to have been a dominant individual in an age of individuals. Galen believed the Hippocratic writings were never wrong—merely obscure—and he saw his own work as the extension and clarification of the Hippocratic corpus; for example, he systematized the theory of the four humors. Nevertheless, Galen was aware of the intervening intellectual progress, saying "the fact that we are born later than the ancients and receive from them the arts in an advanced state, is no small advantage … things that took Hippocrates a long time to discover one can now learn in a few years and one can employ the rest of one's life in the discovery of the things that remain to be learned."

The change in medical thought that Galen produced in his own lifetime was much greater than the changes from Hippocrates's time to his own. When Galen commenced his studies, there were as many "medicines" as there were sects and no criteria for judging "the best sect." He showed that a major source of sectarian conflict and error was due to the lack of philosophical training, which in turn led to "the use of unproven principles," the misunderstanding of "demonstrations," and "a disdain of dissection." Because he accepted the mathematical model of truth, with its criterion of agreement, he claimed that "if conclusions in connection with the cure of disease [were properly] grounded, physicians would manifest an accord like that of geometricians, though it would require [their] learning at the very beginning the meaning of every term, and what undemonstrable propositions commonly called axioms will be accepted."

Galen saw the science of medicine as "based on two criteria, reason and experience," which guaranteed the truth or falsity of its propositions. His systematic anatomical experiments provided a means of demonstrating to the senses those things which no sane man could deny any more than he could deny the self-evident axioms of mathematics. However, among his self-evident axioms we find "Nature [and/or the Creator] does nothing in vain." His frequent appeal to this axiom for explanatory purposes is in part responsible for the overemphasis on the teleological aspects of his writings by both his followers and his critics. Galen's concept of Nature is subtle and complex, and his Creator differs from the Christian God in not being omnipotent but subject to both the laws of necessity and the nature of matter. It was the very success of his program of unification of medical theory that led to its "rigidity" and supremacy in the ensuing centuries.

Most surprisingly, we do not know Galen's family name, because, not wanting to trade on his forebears' reputations, he used only his given name; the name Claudius often associated with him is probably a Renaissance misunderstanding. Galen said of himself, "I have worked only for science and truth and for that reason I have avoided placing my name at the beginning of my books." On the other hand, he was pleased to record Marcus Aurelius's lavish praise that he was "the first of physicians and the only philosopher."

Further Reading on Galen

The translation by M. T. May, Galen: On the Usefulness of the Parts of the Body (2 vols., 1968), contains an excellent introduction and an extensive bibliography. Other translations of his works are R. Walzer, Galen on Medical Experiences (1946); R.M. Green, A Translation of Galen's Hygiene (1951); A.J. Brock, Galen on the Natural Faculties (1952); C. Singer, Galen on Anatomical Procedures: The Later Books (1962); and P.W. Harkins and W. Riese, Galen on the Passions and Errors of the Soul (1964). A few selections can be read in M.R. Cohen and I.E. Drabkin, A Source Book in Greek Science (1948), and L. Clendening, Source Book of Medical History (1960). See also George Sarton, Galen of Pergamon (1954).